The circumscription and distribution of this species has recently been revised (Nesom 2010b, Campbell 2017, Whittemore et al. 2018; and unpublished), and it now appears to be generally octaploid (2n = ca. 184) not hexaploid as previously reported. Widely scattered over eastern states but with a fragmented range, it is concentrated in seasonal wetlands, especially from the Mississippi River lowlands to the southern Great Lakes, and along the Coastal Plain north to se. N.Y. Its range is similar to that of Populus heterophylla (Little 1971; K, PL). In addition to being locally frequent in swamps of the lower Ohio Valley, there are scattered populations on base-rich soils further upstream, especially on glaciated land; however, reports from se. Ohio (K) are erroneous (McCormac 1993). Although virtually unknown in unglaciated parts of the central Ohio Valley (Bluegrass, Knobs and transitions), profunda is expected in peripheral wetlands. There do appear to be vegetative colls. from JEFF (APSC), and across the river it has been found in Jefferson Co., Ind. (at Chelsea Flatwoods; D. Boone, pers. comm.); F. profunda has often been confused with pennsylvanica (or even americana sensu lato), but hybridization has not been demonstrated (Nesom 2010b). It has larger fruits (mostly 40-70 x 6-11 mm versus 20-45 x 4-8 mm), usually with more decurrent wings; larger leaflets (mostly 9-15 x 3.5-7 cm versus 7.5-11 x 2.5-5 cm), usually with more rounded bases and longer petiolules; and petiole bases (or scars on twigs) usually somewhat triangular with a slight notch (versus U-shaped with little or no notch). Young twigs, rachises and leaflets are usually tomentose (versus glabrous to tomentose), but largely glabrous plants are also known further south and may deserve varietal distinction. No state champion is currently recognized by KDF (2020), but the Illinois champion (along Cache Rv.) has been 108 cm dbh, 30 m tall, 17 m wide (Ugent et al. 1980). The Indiana champion (Washington Co.) is 154 cm dbh, 33 m tall, 27 m wide (in.gov/dnr). The Missouri champion (Big Oak Park) is 158 cm dbh, 32 m tall, 24 m wide (mdc.mo.gov).